92-4Runner needing some help

GUYS!! I pulled the plug on the MASS AIR FLOW..and it fired up and STAYED ON!! PLUGGED it back and it and DIED!

Finally figured out the prob! Now I am going to pray CLEANING it fixes it...if not I'll have to buy a new one...but hey lease I know whats the problem!

Thanks guys for the help!! I'll let you guys know how it goes.

:target::target::heh:
 
I was hoping you would find something, because I am having the same issue. I will check mine tonight as well. Mine will start, idle for a second or two, start to stumble and then stall.

I replaced the typical tune-up things (air filter, plugs, wires, oil, filter, fuel filter, pcv, cap, rotor) and still had the same thing going on. I was thinking of trying a tps but didn't want to spend $94 on a hope and prayer. I will definately check this out tonight.

Thanks!
 
LuvDLions said:
I was hoping you would find something, because I am having the same issue. I will check mine tonight as well. Mine will start, idle for a second or two, start to stumble and then stall.

I replaced the typical tune-up things (air filter, plugs, wires, oil, filter, fuel filter, pcv, cap, rotor) and still had the same thing going on. I was thinking of trying a tps but didn't want to spend $94 on a hope and prayer. I will definately check this out tonight.

Thanks!
Click to expand...

Thats exactly what mine is doing! I took it apart and cleaned it with the right Air flow cleaner and its still dieing so I ordered a Air flow system today $200 for a REMAN one, but PRAYING it fixes it!
 
Different car, but on a 92 3000gt unplugging the MAF causes the computer to go into default mode, basically no longer looking at the sensors and instead telling things like the injectors and stuff to act in a default mode. With that car, this was a well known way to hobble home if something acted up. You likely wouldn't pass a smog test, but you could get home.

I'm not familiar with the setup on the 92 4runner, and burned myself out looking at the FSM last week. But I would imagine it would be similar.

Back to the 3000gt, it wouldn't switch to using the sensors until it was warmed up. I had popped off one of the intercooler lines when downshifting, and so air was getting into the system that the MAF didn't sense, and the computer would then muck with the air/fuel ratio. Once it went off default, this would cause stumbling and black smoke out the tailpipe.

What I'm getting at with all of this is to see if your 4runner behaves any different once warmed up vs at a cold start. And if anything changed that you know of before this problem started happening.

If it's working fine when the MAF isn't plugged in, my guess would be it's a sensor of some sort. But if the info from the 3000gt carries over to a 4runner, I wouldn't say it is necessarily the MAF that is the problem.
 
Ok, from the FSM for a 92 4runner, starting at page EM-81, for troubleshooting the v6 engine:
For Engine Stall soon after starting, the order they suggest to troubleshoot is:
Fuel Quality
Fuel Pressure Regulator
Fuel Pump
Fuel Lines
EGR System
Idle Speed Control Valve
Air Flow Meter Circuit
Water Temp sensor circuit
Injectors
Cold Start System
Engine and ECT ECU

So the TPS circuit wasn't even on the list, and for Engine Stall it's only listed (#3) for stalling after the acceleration pedal is depressed. Personally if it is running fine with the MAF disconnected I'd focus on the sensors. But if you have reason to suspect bad fuel (or old fuel) then draining the fuel and putting in fresh could help, or replacing the fuel filter.

Good luck!
 
Air flow sensor ohmed out ok. When I unplugged it, it got worse. Wouldn't run at all. I tried looking into ohming out the tps but I didn't want to make things worse by removing it and not adjusting it right. Now that I read this, I am glad I didn't. Looks like I well have to check out the EGR system and idle speed control valve next.

Thanks again. Hope I didn't jack this thread too bad.


giro said:
Ok, from the FSM for a 92 4runner, starting at page EM-81, for troubleshooting the v6 engine:
For Engine Stall soon after starting, the order they suggest to troubleshoot is:
Fuel Quality
Fuel Pressure Regulator
Fuel Pump
Fuel Lines
EGR System
Idle Speed Control Valve
Air Flow Meter Circuit
Water Temp sensor circuit
Injectors
Cold Start System
Engine and ECT ECU

So the TPS circuit wasn't even on the list, and for Engine Stall it's only listed (#3) for stalling after the acceleration pedal is depressed. Personally if it is running fine with the MAF disconnected I'd focus on the sensors. But if you have reason to suspect bad fuel (or old fuel) then draining the fuel and putting in fresh could help, or replacing the fuel filter.

Good luck!
Click to expand...
 
Whats the mechanical history, things you worked on before this started?

Just a guess: you fixed leaky valve cover gasket, passenger side?
 
bills86e said:
Whats the mechanical history, things you worked on before this started?

Just a guess: you fixed leaky valve cover gasket, passenger side?
Click to expand...

I just bought it. Besides all of the tune-up stuff I have done, I don't know much about it. It was a real dog when I first got it. I changed all of the tune-up stuff, adjusted the throttle cable and kick down cable and it is a little better of a runner now. (mine is a 93 3.0) It still has some noise under the hood, like a valve tick, or something. It is just this intermittent problem with the rpms dropping and wanting to stall occasionally. I just rev the engine and keep it running but, would like to figure it out as it is going to be my sons daily driver.

When I was changing the spark plugs, I removed the air intake hoses for a better view and when I did I was able to see that the drivers side valve cover was loose and leaking bad. I put a socket on it and tightened it down and cleaned it. I'll have to wait and see if it stops the leak I have noticed. I didn't notice a leak on the passenger side. How can you the way everything is slammed in there? The whole underside of the engine is caked with 20 years of oil and sludge so it is hard to tell what is or isn't leaking.

Why would you think I had recently fixed a leaky valve cover gasket?

---
 
giro said:
Ok, from the FSM for a 92 4runner, starting at page EM-81, for troubleshooting the v6 engine:
For Engine Stall soon after starting, the order they suggest to troubleshoot is:
Fuel Quality
Fuel Pressure Regulator
Fuel Pump
Fuel Lines
EGR System
Idle Speed Control Valve
Air Flow Meter Circuit
Water Temp sensor circuit
Injectors
Cold Start System
Engine and ECT ECU

So the TPS circuit wasn't even on the list, and for Engine Stall it's only listed (#3) for stalling after the acceleration pedal is depressed. Personally if it is running fine with the MAF disconnected I'd focus on the sensors. But if you have reason to suspect bad fuel (or old fuel) then draining the fuel and putting in fresh could help, or replacing the fuel filter.

Good luck!
Click to expand...

Well I put the REMAN MAF in it and STILL DID NOT FIX THE PROB...im so lost guys. It idles fine when you pull the MAF connector. Dies when you plug it in....you guys wouldn't think its a Ingition Module would u?
 
4runner-neo said:
Well I put the REMAN MAF in it and STILL DID NOT FIX THE PROB...im so lost guys. It idles fine when you pull the MAF connector. Dies when you plug it in....you guys wouldn't think its a Ingition Module would u?
Click to expand...

Looking at the FSM, while I was under the impression that really only an O2 sensor would throw an error to cause the check engine light to come on, it turns out most of the sensors will, including the MAF. Some have time or speed requirements to throw the error, but from the looks of it if you had the MAF disconnected while running for a bit, that should give an error too.

One option is that there is a sensor going out but it's still not off by enough to cause a Check Engine Light. I'm not an expert at this, and there's lots of guesses I could make, but they wouldn't necessarily be in the quickest direction.

Personally, I'd unplug the MAF, start up the 4runner, and let it idle for 10 minutes. If that works you can toss out some things (like fuel quality, fuel lines, fuel pump, fuel relay, fuel filter, plugs, etc). Turn it off, plug back in the MAF, and try to start it again now that it's warmed up.

That should narrow it some, and might even give you a CEL that you could work with.
 
Well I did that...I unplugged the MAF and let it run until it got warm. As it got warmer it started to loose idle and eventually died. I plugged the MAF back in and it did same thing....but I noticed like it was TRYING to stay fired up but then died. I noticed the CHECK ENGINE light blinked twice but then it died.


On the up side...when its cold it sounds really good lol....

What you think?
 
4runner-neo said:
Its the ECU guys....:(....took it to dealer.
Click to expand...

Did they say anything about the ECU, in what was wrong? Have many people had ECU problems with age? Did they hook it up to a good ECU and have it work fine?

The reason I ask is with a 92 3000gt it was well known and common for the ECU to die because the capacitors would go bad, and then leak all over the board and ruin the board. The feeling was "they're all going to go bad, it's just a matter of when". I forget what the rating on the capacitors was, but my remembrance was that they used the best electrolyte at the time, but that the best still had a limited life, especially in a hot situation. So cars in cooler environments or kept out of the sun did better. The car I was fixing up had started to leak, but with some cleaning and $4 of parts from Frys it was fixed before going bad.

I haven't looked in my 92 4runner ECU. But I'm curious if it's a problem we have to worry about, now or in the future.
 
giro said:
Did they say anything about the ECU, in what was wrong? Have many people had ECU problems with age? Did they hook it up to a good ECU and have it work fine?

The reason I ask is with a 92 3000gt it was well known and common for the ECU to die because the capacitors would go bad, and then leak all over the board and ruin the board. The feeling was "they're all going to go bad, it's just a matter of when". I forget what the rating on the capacitors was, but my remembrance was that they used the best electrolyte at the time, but that the best still had a limited life, especially in a hot situation. So cars in cooler environments or kept out of the sun did better. The car I was fixing up had started to leak, but with some cleaning and $4 of parts from Frys it was fixed before going bad.

I haven't looked in my 92 4runner ECU. But I'm curious if it's a problem we have to worry about, now or in the future.
Click to expand...

When I talked to him before he was waiting one some kind of relay(forget which one he said :() to replace and he said if it was this relay, then it was the ECU. He said they scanned it and they did research on common problems with this year and he said there were several people that the ECU went out on them and very few that the relay went out. So guess we will see? $85 part off ebay
 
Finally got my truck back today guys!!! And it WAS the ECU!! I hope this post helps some of you!! It truly was a long, exhausting battle!

Thanks everyone that tried to help me!

I'm back on the road!!! :first::second::third:
 
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